Appeal to the majority
An appeal to the majority (also called argumentum ad populum) is the logical fallacy of believing that because something is popular, it is right.For example, using the argument that most Americans support the death penalty as an argument for the death penalty is an appeal to the majority and does not logically support the argument.
The appeal to the majority is a modification of the logical fallacy appeal to authority, in that greater numbers are thought to give greater authority to a position or action.